Optical devices having barrier layers to facilitate reduced hardmask diffusion and/or hardmask residue, and related methods

Abstract

Embodiments of the present disclosure generally relate to optical devices having barrier layers for reduced hardmask diffusion and/or hardmask residue, and related methods of forming the optical devices. In one or more embodiments, a plurality of optical device structures each include a barrier layer disposed between a device function layer and a hardmask layer prior to removal of the hardmask layer.

What is claimed is: 
     
         1 . A device, comprising:
 a transparent substrate; and   one or more optical device structures disposed on a surface of the substrate, each of the one or more optical device structures comprising: 
 a device function layer formed of a metal oxide, the device function layer having a first refractive index, and 
 a barrier layer disposed above the device function layer, the barrier layer having a second refractive index that is less than the first refractive index; 
   wherein an atomic percentage concentration of a hardmask material is less than 0.7% throughout each of the one or more optical device structures, the atomic percentage concentration comprising: 
 a surface atomic percentage concentration (SAP) on an outer surface of each of the one or more optical device structures, wherein the surface atomic percentage is less than 0.7%, and 
 a volumetric atomic percentage concentration (VAP) along a height of each of the one or more optical device structures, wherein the VAP is less than 0.7%. 
   
     
     
         2 . The device of  claim 1 , wherein the one or more optical device structures are formed at least by wet etching a hardmask layer disposed on the barrier layer, and the hardmask layer is formed of the hardmask material. 
     
     
         3 . The device of  claim 2 , wherein the atomic percentage concentration of the hardmask material is 0.3% or less throughout each of the one or more optical device structures. 
     
     
         4 . The device of  claim 1 , wherein the transparent substrate is formed of glass. 
     
     
         5 . The device of  claim 1 , wherein the metal oxide includes a titanium oxide (TiO) or a niobium oxide (NbO). 
     
     
         6 . The device of  claim 5 , wherein the barrier layer is formed of a silicon oxide (SiO), a silicon nitride (SiN), a ruthenium oxide (RuO), or a tantalum oxide (TaO). 
     
     
         7 . The device of  claim 5 , wherein the barrier layer is formed of silicon dioxide (SiO 2 ). 
     
     
         8 . The device of  claim 5 , wherein the hardmask material includes one or more of chromium (Cr), a chromium oxide (CrO), ruthenium (Ru), carbon (C), a titanium nitride (TiN), a tantalum nitride (TaN), or an aluminum nitride (AlN). 
     
     
         9 . The device of  claim 1 , wherein each of the one or more optical device structures further comprises:
 an encapsulation layer disposed at least partially between the device function layer and the barrier layer.   
     
     
         10 . The device of  claim 9 , wherein the encapsulation layer is formed of silicon dioxide (SiO 2 ). 
     
     
         11 . The device of  claim 1 , wherein the device function layer has a first density, and the barrier layer has a second density that is greater than the first density. 
     
     
         12 . The device of  claim 1 , wherein the barrier layer has a thickness within a range of 5 nm to 50 nm. 
     
     
         13 . A method of forming a device having a plurality of optical device structures, comprising:
 positioning a transparent substrate;   forming one or more device function layers on a surface of the transparent substrate, each of the one or more device function layers formed of a metal oxide and having a first refractive index;   forming one or more barrier layers above the one or more device function layers, each of the one or more barrier layers having a second refractive index that is less than the first refractive index;   forming a plurality of hardmask layers above the one or more barrier layers, each of the plurality of hardmask layers formed of a hardmask material;   conducting a first etching operation that selectively etches the device relative to the plurality of hardmask layers; and   conducting a second etching operation that selectively etches the plurality of hardmask layers to remove the plurality of hardmask layers.   
     
     
         14 . The method of  claim 13 , wherein the one or more barrier layers are formed above the one or more device function layers using a physical vapor deposition (PVD) operation, the PVD operation comprising:
 reacting one or more process gases with a target having silicon (Si), the one or more process gases including one or more of argon (Ar), krypton (Kr), neon (Ne), or oxygen (O).   
     
     
         15 . The method of  claim 14 , wherein:
 the reacting of the one or more process gases with the target occurs while maintaining a process volume at a process pressure within a range of 1.0 mTorr to 50 mTorr; and   the method further comprises generating a process plasma, the generating of the process plasma including supplying a pulsed direct current (DC) electrical power to the one or more process gases.   
     
     
         16 . The method of  claim 13 , wherein:
 the first etching operation selectively etches the one or more device function layers relative to the plurality of hardmask layers to remove device portions of the one or more device function layers; and   the second etching operation selectively etches the plurality of hardmask layers relative to the transparent substrate to remove the plurality of hardmask layers.   
     
     
         17 . The method of  claim 13 , further comprising, prior to the forming of the one or more barrier layers:
 forming one or more encapsulation layers at least partially above the one or more device function layers,   wherein the one or more barrier layers are formed above the one or more encapsulation layers and the plurality of hardmask layers are formed above the one or more barrier layers.   
     
     
         18 . The method of  claim 17 , wherein:
 the first etching operation selectively etches the one or more encapsulation layers relative to the plurality of hardmask layers to remove encapsulation portions of the one or more encapsulation layers; and   the second etching operation selectively etches the plurality of hardmask layers relative to the transparent substrate to remove the plurality of hardmask layers.   
     
     
         19 . The method of  claim 13 , wherein the second etching operation includes wet etching. 
     
     
         20 . A device, comprising:
 a transparent substrate; and   one or more optical device structures disposed on a surface of the substrate, each of the one or more optical device structures comprising: 
 a device function layer formed of a metal oxide, the device function layer having a first refractive index, and 
 a barrier layer disposed above the device function layer, the barrier layer having a second refractive index that is less than the first refractive index; wherein: 
 a surface atomic percentage concentration (SAP) on an outer surface of each of the one or more optical device structures is less than 0.7%, and 
 a volumetric atomic percentage concentration (VAP) along a height of each of the one or more optical device structures is less than 0.3%, wherein the VAP is 0.1% or less beginning at a depth and throughout a remaining height of each of the one or more optical device structures, and the depth is within a range of 0.1 nm to 108 nm.